AO Smith Water Heaters
Review and Buying Tips

Explore the benefits of the most popular and advanced AO Smith water heaters. Find the review of the electric and gas models, including hybrid, tank and tankless type, for heating domestic water.

AO Smith is one of the largest manufacturers of water heaters in North America. For over 70 years AO Smith is designing and producing HVAC equipment with numerous patents, models, and brands in their possession. The most popular models are coming from the Vertex and Voltex series that include tank-type water heaters with the condensing and heat pump technology, also tankless and POU type.

AO Smith water heater

If looking for the best model, you can search for one with the cutting-edge technology and most advanced features, or check out the AO Smith catalog or brochure where the company already classified them as the Good, Better and the Best. This is what makes your search easy. 

AO Smith is the owner and manufacturer of the following brands:

AO Smith corporate office is at 500 Tennessee Waltz Parkway, Ashland City, TN 37015, USA and the phone number is 800-527-1953.

AO Smith water heater review

Choose a type

Both gas and electric tank-type heaters consist of three groups:

Proline – cheap, low efficient and shorter warranty (Good solution)

Proline Master – affordable, better efficiency and longer warranty (Better solution)

Proline XE – low operating costs, expensive, longest warranty and premium features (Best solution)



Gas water heaters from AO Smith are designed in many types and models; atmospheric, power vent, direct vent, power direct vent, high efficient, low NOx, high capacity, fast recovery, tankless and other, and for any home sizes and hot water demand requests. From the economy to highly advanced Vertex models that AO Smith makes – select the best one that fits all your needs for hot water and at the same time can save and last.

If looking for the best gas tank-type water heater for your large home and ultra-high efficient water heating, consider Vertex. AO Smith Vertex series offers several models and two sizes, all utilizing condensing technology, power vent and power direct vent option. They include commercial-grade elements such as the spiral heat exchanger, advanced electronics, side taps for recirculation, two heavy-duty anodes, and more. These can achieve ultra-high efficiency of over 96%, which maximizes savings.

AO Smith Polaris is another group of tank-type water heaters with the condensing technology that is recommended for those who want the best. Models come with the stainless steel construction, modulating gas burner and premium features, making it one of the preferable models to buy. They offer amazing specs, such as the first-hour rate of over 179 gallons, recovery rate up to 253 gallons, and efficiency of 96%.


If natural gas and LP water heaters are not the right solutions for your home, then electric water heaters might be. They are cheaper, simpler, easy to install, and maintain. Electric water heaters are mainly built for the whole house water heating, but there are also models such as Lowboy, Compact, Table Top, tankless, and small point-of-use models with the lower capacity and special applications.

The best models are coming from the Proline XE group, available in sizes from 40 to 55 gallons designed tall and short. They utilize the electronic user interface with the touch screen, diagnostic system, and multiple operating modes for user convenience.

Read more about AO Smith electric water heaters.

Heat pumps

AO Smith Voltex heat pumps are the best from electric-powered water heaters because they come with the ultra-high energy factor, Energy Star qualifications, and some amazing features and specs. Users will enjoy a substantial reduction in water heating costs, multiple choices of operating modes, the user-friendly electronic interface for better accuracy, easier diagnostics, comfort, and convenience.

AO Smith heat pumps can be found in three sizes, with the tank capacity from 50 to 80 gallons, warranties of 6 and 10 years, and maximum energy factor of 3.42.

Read more about Voltex heat pumps.

Features of tank-type heaters

Majority of the electric and gas-powered AO Smith hot water heaters are designed with the following commercial-grade features:

  • DynaClean system is the self-cleaning system that reduces the sediment build-up while increasing the heater's performance. It is built from tough materials so it can withstand high temperatures and resist premature failure due to water chemistry.
  • The Green-Choice gas burner is the environment-friendly burner that is designed to reduce NOx emission by 33% on all gas models.
  • CoreGuard anode rod is the magnesium or aluminum rod with the stainless steel core used to protect the tank from the aggressive water action. It helps increase the longevity of the metal storage tanks. Top models usually have one heavy-duty anode or multiple rods so that the manufacturer can include a longer warranty.
  • Blue Diamond glass coating is used to protect the inside surface of the tank from corrosion. This is another commercial-grade feature that works together with the anode to protect the metal tank from corrosion.

Other quality components that are found in AO Smith water heaters are the brass drain valve with the enhanced flow, heat traps which help in energy loss reduction, electric heating elements and gas valves equipped with the microprocessor and LED status indicator.


If looking for the gas heaters that can produce hot water on demand and with the continuous water flow, AO Smith water heaters with the tankless technology might be the answer for you.

AO Smith tankless units for residential water heating are small and wall-hanging, and due to its high-efficient operation are Energy Star approved. AO Smith tankless water heaters are designed for indoor and outdoor installation and based on different water flow and power, can supply enough hot water from smaller homes to larger houses with multiple bathrooms.

When we talk about specs, AO Smith tankless are amazing. They heat water using the powerful eco gas burners with up to 199,900 BTU gas input, reaching high efficiency of up to 0.96 and delivering up to 10 GPM of hot water, making them ideal for homes with multiple baths. They are backed by a 15-year warranty.

Check out the detailed review to see different types such as the ultra-low NOx non-condensing and condensing, and find out the differences, benefits, and advantages over other types.

AO Smith also has a solution for those homeowners looking for more power and ultra-efficient water heating. These water heaters are known as condensing, and as the non-condensing units, they are eligible for government tax credits. Condensing technology is found not only in the storage tank type but tankless too.


Residential boilers from AO Smith are built to heat not only domestic water but home space as well. Boilers are similar to tankless; they utilize the flat plate heat exchanger and fire tube both made of stainless steel, built-in recirculation pump, LCD display, and diverter valve to direct water either for water or space heating, using the external space heating loop.

Boilers are available in three sizes; providing the maximum power of 199,999 BTU, turn-down ratio of 10:1, maximum temperature of 190 F, and water flow output of up to 9.2 GPM.

All the models are built for indoor installation only, and due to its eco-friendly burner, they meet ultra-low NOx requirements. The warranty is 10 years.


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Problem and flashing display on AO Smith GAHH 50 
I have the tank-type gas water heater from AO Smith manufacturer, model Effex GAHH-50. This is the high efficiency unit with the atmospheric venting and …

Converting atmospheric vent to direct or power vent? 
I am planning to upgrade my gas water heater atmospheric or natural draft flue with a DV or PV type. I have a small house with a basement where I am planning …

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